They left their Ohio State careers with an exclamation point. Now they pursue their NFL dreams as question marks.

The Buckeyes’ 12-0 season in 2012 will forever be cherished memories to the seven OSU football players going to the NFL combine this week in Indianapolis. Their legacy as leaders on only the sixth undefeated team in school history is secure. But nothing about their pro careers is.

Take Nathan Williams, who beat the odds by returning from microfracture knee surgery to play his senior season. A defensive end for Ohio State, Williams’ best chance in the NFL probably is as a linebacker. Defensive end John Simon might be asked to make a similar transition. Zach Boren, whose switch from fullback to linebacker solidified the Buckeyes’ defense in the stretch drive, is not sure what position he will try to play in the pros.

Defensive tackle Johnathan Hankins is projected to be a first-round pick. It’s too early to predict with any confidence when, or in some cases if, the others will be drafted.

Williams is just grateful to have put himself in position to be drafted. He estimates that he played last year at about 80 percent because his left knee was still regaining strength.

“It’s scary to think I played this season not being close to 100 percent,” Williams said. “I don’t think Ohio State really saw the real Nathan Williams.”

For the last two months, Williams — along with Jake Stoneburner and Reid Fragel — have been working out at the Performance Enhancement Professionals facility in Arizona.

“I usually get in at 8 in the morning and don’t leave until 3 or 4 in the afternoon,” Williams said. “They’re grueling workouts we have to go through. But at the end of the day, it’s very rewarding knowing you got better.”

Williams is confident that he will impress NFL scouts.

“You have to have confidence, or you’ll be left in the dust,” he said. “I’m confident in my abilities, always have been. I think whatever team takes me will have a pleasant surprise.”

Williams suspects that the transition to linebacker will be easy. He believes that’s his natural position and it’s what he played before coming to Ohio State. But his easiest path to early playing time as a Buckeye was at defensive end, so that’s where he played.

Williams said he asked coaches to play him at linebacker in midseason during the worst of the Buckeyes’ defensive struggles. Because his knee prevented him from practicing much, coaches were understandably wary of making the switch.

At the East-West Shrine game, Williams did play as a linebacker and he believes he did well. The knee, he said, is no longer an issue.

“I have no discomfort at all, thank God,” he said. “The type of effort that I had to put in during rehab and the work ethic I displayed, I took it very seriously. I think my knee is thanking me for that. The hesitation is gone. I’m able to not think about it at all like I used to.”

Simon and Fragel were invited to the Senior Bowl, the most prestigious of the postseason all-star games/evaluation camps. But both players left early because of injuries described as minor.

The Big Ten’s Defensive Player of the Year, Simon is considered off the charts in terms of leadership and work ethic. But figuring out his best position could be an issue. He is considered a bit of a ’tweener between defensive end and linebacker in the pros.

“That’s up to the organization to decide,” Simon said. “That’s not for me to decide. I’m just blessed to have the opportunity to play at the highest level.”

After a shaky start, Fragel made his move from tight end to right tackle pay dividends. His big frame and athleticism will make him attractive to NFL teams.